Forced air oven



1968 G. R. EVERSON ETAL 3,411,493

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LMLLl AM JIM-(65 QPUEQ i'fskee United States Patent 3,411,493 FORCED AIR OVEN George Richard Everson and William James Walter Booker, London, England, assignors to G. R. Everson and Sons Limited, London, England, a company of England Filed July 24, 1967, Ser. No. 655,523 Claims priority, application Great Britain, Aug. 11, 1966, 36,048/66 11 Claims. (Cl. 126-21) ABSTRACT OF THE DISCLOSURE An oven in which the base wall has a centrally arranged V-shaped depression to direct air heated by a burner through ducts along both sides and the rear of the oven. A fan in the rear circulates the air around the oven in a manner preventing the formation of excessively hot or cold spots.

The invention relates to ovens of the kind in which air is circulated to provide an eflicient and even heating of the content.

In particular the invention relates to ovens which may be used for cooking or at least re-heating precooked food.

However, such ovens can be used for other purposes. The oven may be heated in any known manner although gas and electric heating have been found preferable as accurate control of temperature can readily be attained.

Ovens of the type referred to above are known as forced air ovens and the air which is circulated therein does not change and therefore there is no heat lost in heating fresh air from outside the oven. The flue gases of the oven in no way come into contact with the air within the oven.

It has been proposed to provide a forced air oven suitable for use for catering purposes which is gas heated. Such ovens have means for circulating air therein, a plurality of gas jets adapted to heat the base of the oven, or at least an air space below the base; the air from such space first flowing through channels formed between the inner and outer walls of the oven and then escaping through a vent or chimney.

In such an oven a fan driven by an electric motor circulates the air so that heat is distributed throughout the oven.

However, it has been found that such circulation of air is not entirely satisfactory as excessive hot or excessive cool spots tend to develop.

An object of the present invention is to eliminate such hot and cold spots and to provide an oven which is substantially uniformly heated throughout.

A further object of the present invention is to provide an oven of the kind referred to having a base plate which can be removed from the oven, said base plate readily forming a drip tray. The edges of the base plate may be turned upwardly.

A still further object of the present invention is to provide an oven of the kind referred to wherein the base of the oven comprises a metal sheet having a V-shaped depression in the central region thereof.

The oven with such a depression may have gas burners positioned to each side of the V-shaped depression such that the flue gases produced by the burners flow respectively to opposite sides of the oven. Advantageously the V-shaped depression extends in a front to rear direction so that the flue gases tend to flow to the sides of the oven.

A still further object of the invention is to provide an oven of the kind referred to wherein the base of the oven is provided with a plurality of depending studs. Said studs 3,411,493 Patented Nov. 19, 1968 may be formed of copper coated steel or other material having a high coeflicient of heat transfer. Moreover, the studs may be formed with flanges to provide a maximum area for heat transfer.

Another object of the present invention is to provide an oven of the kind referred to wherein heating means for heating the oven is mounted in a drawer positioned beneath the oven, such that the drawer may be opened to provide access to the heating means. The drawer may also include the control apparatus for the oven.

The above and other objects are accomplished in accordance with this invention with a forced air oven comprising a back wall, a rear plate spaced from the back wall and defining an aperture therein, side walls connected to the back wall, a base wall secured to the back wall, and a top wall secured to the back and side Walls. The rear plate has edges extending to positions short of the side and base walls to define marginal strips between the rear plate edges and the side and base walls. Fan means is associated with the aperture in the rear plate for moving air therethrough, and baffle members are disposed between the rear plate and the back wall. Means is provided for directing air flowing through the marginal strips at the base of the oven to the marginal strips at the sides of the oven, which may be a base plate and a baffle member disposed beneath the base plate.

In the illustrated embodiment, there is a V-shaped depression in the central region on the base wall of the oven, and a plurality of depending studs are provided on the base wall of the oven. Flanges are formed on the studs which have a high coefficient of heat transfer.

A drawer may be positioned beneath the base wall, and a burner is mounted in the drawer, the drawer being operable to provide access to the burner.

Other objects and a fuller understanding of the invent-ion may be had having reference to the following description and claims taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a perspective view showing a forced air oven constructed in accordance with the present invention;

FIGURE 2 is a front view of the oven shown in FIG- URE 1 with the doors removed;

FIGURE 3 is a section on the line XX of FIGURE 2;

FIGURE 4 is a plan view of the base of the oven shown in FIGURES l to 3; and

FIGURE 5 is a section on the line YY of FIGURE 4.

Referring to the drawings, the oven comprises an outer steel casing having sides 10, a top 11, a front panel 12 and legs 13. Vertically hinged are two doors 14 which have glass panels 15 permitting the interior of the oven to be examined whilst the doors are closed.

As shown in FIGURES 2 and 3, the oven has at its back a rear plate 16 behind which is a fan motor 17 provided with a blade comprising a thin disc 18 having welded thereto a plurality of vanes 19. The fan is in alignment with an aperture 20 and the vanes 19 are sufliciently close to the aperture 20 that air may be drawn through the aperture and distributed outwardly from the fan in the space formed between the rear plate 16 and the back wall 21 of the oven. In this space there are positioned three baflles 22 for directing air drawn through the aperture 20 by the fan. Formed in the rear plate 16 of the oven are two series of apertures 23 which are used to permit light from one or more electric lamp bulbs positioned between the plate 16 and the back wall 21 to illuminate the oven. The electric lamp bulbs are not shown but are protected by heat resistant glass covering the apertures 23.

It will be seen that the rear plate 16 does not extend completely to the base, top or side walls of the oven and thus air may be drawn through the aperture 20, passed round the baffles 22 and into the cooking space of the oven through the gaps formed between the rear plate 16 and the base, side walls and top of the oven.

The top, rear and other parts of the oven are lined with insulating material 24, with a view to retaining heat within the oven. The oven is heated by gas jets carried on tubes 31 from a gas conduit 32. The rows of gas jets 30 extend from front to rear of the oven substantially centrally and are positioned beneath the base wall 25 of the oven, Which is formed of sheet metal having therein a triangular shaped depression 26. This depression has the eifect of dividing the heat output from the heater system in such a way that the hot gases produced from one of the rows of the burner passes to one side of the oven, whilst that produced by the other burner passes to the other side of the oven. The hot gases pass between the outer and inner side walls of the oven in channels 33 to the top of the oven where there are arranged a plurality of rectangular tubes 34 which direct the hot gases to a central passageway 35 from which the gases emerge from the oven through a flue outlet 36.

The base wall 25 carries a plurality of projecting studs 27, which are formed of copper, copper coated steel or other material having a high coeflicient of heat transfer. These studs may be formed with flanges (like a screw thread) to provide maximum surface area and may be riveted to or welded to the base wall.

The burner system is carried in a drawer 40, the front panel 12 of which is formed with a viewing aperture 42 beneath which and inclined thereto is positioned a mirror (not shown) by which the gas jets and pilot burner may be viewed. A control panel 41 mounted on the front panel 12 is provided with various switches to operate the fan, gas jets and the timing mechanism. Naturally thermostatic sensing means is provided to maintain or regulate the heat in the oven and an alarm bell is also provided, which can be arranged to sound when a cooking operation is complete.

The fact that the burners and control unit are mounted in a drawer means that in the event of servicing being required access thereto is readily obtainable. Moreover faulty units can quickly be replaced.

Within the oven is a trolley mounted on castors 51 and carrying a plurality of wire trays 52. These trays 52, since they are of wire, do not impede the flow of hot air within the oven. Immediately above the castors is provided a base plate constituted by drip tray 53 which extends over the area underneath the trays and is formed with a battle 54 which extends in such a way that air issuing from the gap between the rear wall 16 and the base plate 25 of the oven and flowing underneath the drip tray 53 is directed to each side of the oven. The trolley with loaded trays may therefore easily be withdrawn from the oven.

The legs 13 of the oven are adjustable so that the height thereof may be varied.

In operation two gas flows move as follows:

The air within the oven is drawn through the aperture 20 by the fan driven by motor 17 into the space between the rear plate 16 and back wall 21 of the oven. The air then flows in the direction of the arrow and is expelled near the top, base and side walls of the oven. Some of the air hits the baflie 54 and is directed outwardly, but when the air reaches the front is flows towards the middle of the oven and then again through the aperture 20.

The hot gases from th gas burners flow in the direction illustrated by the arrows 61 underneath the base wall 24 between the studs 27 and then upwardly through the passages formed in the sides of the oven, through the tubes 34 of the oven to the duct 35 and then to the flue outlet 36.

Food is positioned on the racks of the trolley, which is then or previously has been placed in the oven, the doors closed and the cooking time and temperature set on the appropriate dials on the control panel 41. When all is set the cooking procedure is put into action and a pilot flame ignites the burners 30; this can be inspected through the aperture 42. At the same time the fan 17 is started and circulates air within the oven. When the oven has reached the required temperature the burners will be extinguished, but the air will still be circulated within the oven by the fan which remains in operation. When the oven temperature falls below a pre-selected temperature, the burners are again ignited.

When the cooking time has been completed the gas jets, if alight, are extinguished and the fan stopped. The latter will, of course, remain rotating for a few minutes. The alarm bell then rings to advise that the food is ready.

Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and numerous changes in details of construction and the combination and arrangements of parts may be resorted to without departing from the spirit and the scope of the invention hereinafter claimed.

We claim:

1. A forced air oven comprising in combination a back wall; a rear plate secured in spaced relationship to said back wall, said rear plate defining an aperture therein; side walls connected to said back wall; a base wall secured to said back wall and said side walls; a top wall secured to said back wall and said side walls, said rear plate having edges extending to positions short of said side walls and said base wall; marginal strips defined between the rear plate edges and said side walls and said base wall; fan means associated with the aperture in said rear plate for moving air through said aperture; baflle memhers disposed between said rear plate and said back wall; means for directing air flowing through said marginal strip at the base of the oven to the sides of the oven; a central region on the base wall of the oven and a V-shaped depression in said central region.

2. The oven according to claim 1, in which said V- shaped depression extends in a front to rear direction.

3. The oven according to claim 2, including gas burners positioned to each side of said V-shaped depression.

4. The oven according to claim 3, including a plurality of depending studs provided on the base of the oven.

5. The oven according to claim 4, in which said studs are formed of a material having a high coeflicient of heat transfer.

6. A forced air oven comprising in combination a back wall; a rear plate secured in spaced relationship to said back wall, said rear plate defining an aperture therein; side walls connected to said back wall; a base wall secured to said back wall and said side walls; a top wall secured to said back wall and said side walls, said rear plate having edges extending to positions short of said side walls and said base wall; marginal strips defined between the rear plate edges and said side walls and said base wall; fan means associated with the aperture in said rear plate for moving air through said aperture; baffle members disposed between said rear plate and said back Wall; means for directing air flowing through said marginal strip at the base of the oven to the sides of the oven; a central region on the base wall of the oven; a V-shaped depression in said central region; a plurality of depending studs provided on the base wall of the oven; flanges formed on said studs and said studs having a high coeflicient of heat transfer.

7. A forced air oven comprising in combination a back wall; a rear plate secured in spaced relationship to said back wall, said rear plate defining an aperture therein; side walls connected to said back wall; a base wall secured to said back wall and said side walls; a top wall secured to said back wall and said side walls, said rear plate having edges extending to positions short of said side walls and said base wal marginal strips defined between the rear plate edges and said side walls and said base wall; fan means associated with the aperture in said rear plate for moving air through said aperture; bafile members disposed between said rear plate and said back wall; means for directing air flowing through said marginal strip at the base of the oven to the sides of the oven; a central region on the base wall of the oven; a V-shaped depression in said central region; a plurality of depending studs provided on the base wall of the oven; flanges formed on said studs and said studs having a high coeflicient of heat transfer; a drawer positioned beneath the base wall of the oven; a burner mounted in said drawer and said drawer being openable to provide access to said burner.

8. A forced air oven comprising in combination a back wall; a rear plate secured in spaced relationship to said back wall, said rear plate defining an aperture therein; side walls connected to said back wall; a base wall secured to said back wall and said side walls; a top wall secured to said back wall and said side walls, said rear plate having edges extending to positions short of said side walls and said base wall; marginal strips defined between the rear plate edges and said side walls and said base wall; fan means associated with the aperture in said rear plate for moving air through said aperture; bafl le members disposed between said rear plate and said back wall; means for directing air flowing through said marginal strip at the base of the oven to the sides of the oven, said means for directing air at the base of the oven comprising a base plate spaced from said base wall and a baffle member disposed beneath said base plate; a plurality of depending studs provided on the base of the oven; flanges formed on said studs and said studs being made of a material having a high coeflicient of heat transfer.

9. The oven according to claim 6, in which the means for directing air at the base of the oven comprises a base plate spaced from the base wall, said base plate being removable from the oven.

10. The oven according to claim 9, including upwardly directed marginal flanges at the edge of said base plate.

11. The oven according to claim 6, in which said baflle members are disposed in a substantially vertical plane and extend only for part of the height of said rear plate.

References Cited UNITED STATES PATENTS -1/l952 Sanford et a1. l26-21 1/1963 Keating 126-21 

